An experimental design is used to assign variables for testing. In contrast to a control design where nothing is changed, the experimental design allows you to test various new inputs to see how they would vary from the original results.
Answer:
A. The wavelengths of the new sound waves are longer
Explanation:
This is the Doppler effect which can be best illustraded for the case of a siren of an ambulance approaching us having a greater frequency and getting lower in frequency and deeper as the ambulance passes us.
Since the wavelength is inversely proportional to the frequency it follows the wavelengths are longer when the frequency decreases lowering its pitch and getting deeper.
The answer is either C or D..
You would get 13.7
mi/51mm=3.5mm/13mm
by solving it you will B13.7mm
